1. Field of the Invention
The present invention relates to a water-based ink for ink jet recording, an ink cartridge, a water-based ink set for ink jet recording, an ink jet recording method, and an ink-jet recording apparatus.
2. Description of the Related Art
Conventionally, a water-based ink for ink-jet recording, which is blended with triethylene glycol monobutyl ether as a penetrant for adjusting the drying speed on the recording medium, is used generally and widely.
Such a conventional water-based ink is excellent in the discharge stability when a head is maintained in an uncapped state and the drying performance on paper surface. If any problem arises in relation to the discharge stability obtained when the head is maintained in the uncapped state, a water-based ink undergoes the increase in viscosity in a period of time shorter than a desired maintaining time and the discharge characteristic is deteriorated, although it is intended to maintain the stability of the discharge for a period of time as long as possible. The drying performance on paper surface means the easiness of the drying caused when a water-based ink is discharged on the recording medium. However, in the case of the water-based ink as described above, any compound, which originates from the material for forming an ink jet recording apparatus, is eluted into the water-based ink in some cases. The material, which forms the ink jet recording apparatus as described above, is exemplified, for example, by a rubber member and a member of organic material other than rubber material. The rubber member is exemplified, for example, by a wiper and a cap. The wiper wipes, for example, a nozzle surface of the ink jet head. The cap shuts off, for example, the nozzle surface from the external environment. If any compound, which originates from, for example, the rubber member, is eluted into the water-based ink, the compound is deposited in the water-based ink in some cases. If the compound is deposited, for example, it is feared that the nozzles of the ink-jet head may be clogged-up.
On the other hand, a treatment solution (process liquid), which contains an aggregating agent such as a polyvalent metal salt or the like for causing a colorant contained in a water-based ink to aggregate, is used in some cases before performing the ink jet recording by using the water-based ink in order to improve the optical density (OD value) of a recorded matter. When a water-based ink set for ink jet recording, in which the water-based ink and the treatment solution are combined, is used, then the optical density (OD value) of the recorded matter is improved, but the total liquid amount is increased on the recording medium due to the use of the treatment solution. Therefore, the drying performance on paper surface is deteriorated. The drying performance on paper surface means the easiness of drying when the water-based ink and the treatment solution are applied onto the recording medium.